Nickel plating process and solution



ice

n 2,978,391 Patented Apr. 4, 1961 The subscript n above has the significance of an integer from 1 to 4, while m also indicates an integer from 1 to 4. Again two of the characteristic groups may be connected through an alkoxy group having from 1 to 4 carbon hydrocarbon linkage as:

The second addition agent, which-cooperates withrthe brightener 'in bright, acid, nickel plati solutions fall 7 g 7 into the category of organic sulfonamidesr sulfiuiide's, The organic sulfonates. sulfinii'des'andsulftfi sulfonates. amides, according to the invention; com

NICKEL PLATING PROCESS AND SOLUTION atoms. Also, it is not essential to have two of the characteristic groups in the molecule. One of them may Arthur H. Du Rose, Euclid, Ohio, assignor to The Har- I Shaw Chemical Company, Cleveland, Ohio, 3 coulomb be connected to various other groups such as alkyl groups, fion of Ohio alkenyl groups, alkynyl groups and groups made up of two or more of alkyl, alkenyl and/or alkynyl groups N0 Drawmg' Filed 1958, Nil-757,123 10 having from 1 to 4 carbon atoms. The characteristic Claims. CL 4 group may be connected to an amino group or alkyl substituted ammo group. The alkoxy compounds corresponding to the thioalkylene nitriles and the thiodialkylene nitriles may be called thioalkoxy nitriles and This invention relates to the electrodeposition of nickel thiodialkoxy itril Y a more Specifically to a Process of electrodepositing Thus a general formula for compounds containing the nickel, and to a solution for use in a process for electrocharacteristic grouping, z)n may be Written; depositing nickel. The invention has to do with the A S (CH CN, whe n i a integer from 1 to 4 i v ry of per ing rig t g agents Sultable for and A is selected from radicals of the class consisting of: use in aqueous acid nickel plating solutions where the (1) NO (CH2)D v solution contains a nickel electrolyte selected from nickel 2 Noonouswnam, 711. being an integer from 1 to 4. sulfate and nickel chloride and mixtures thereof. 355 fff f gflg ifg gfl According to the discovery, excellent bright, ductile s Alkynyl (1 too 4 gafiboll atoms);

' u up and smooth deposits of mckel can be produced over a gg gg z integer from no wide cathode current density range by electrolyzing an R aqueous acid solution of a nickel electrolyte of the class consisting of nickel sulfate, nickel chloride and mixtures x of nickel sulfate and nickel chlon'de if the solution also 8) O-,whereRis independentlyHor alkyl,alkenyl or alkyny contains an efiective amount of each of two cooperating to 4 addition agents.

' b b t t d t CH h t s u 0 One of the cooperating addition agents has an internal ibogfiili gfigdg Sn 8 1m e or W erevar 1 m t Sulfur f molecul? and 1s characwnzed The addition agents falling within this classification by a solubihty m the platmg .Solutlon of i .least 9 will hereafter be referred to as brighteners. Typical gram per hter and the q i q n i s brighteners according to the invention are indicated in z)nh charactmstlc fgroupmg may Table I. The optimum range of each brightener which be found a number of 9 related W of should be dissolved in the plating solution is also indit whlcil may be cane? thloalkylene A cated in Table I in grams of brightener per liter of plating slrab 6 type 18 the symmemcal form solution. They may be used in the plating solution in 'NC-(CH -S--(CH ),,CN 40 concentration from 0.0001 to 0015.

TABLE 1 Optimum Range, Grams per liter 6,B-Thiodipropionitrile NCCHzCHzS-CHzOHz-ON. 00055006 a,n -Thiodiethanenitrile NO-OHZSOHQ,ON 0005:.006 1,2-bis-(fi-Oyanoethylmercapto)ethane N O-CHiOHr-SCHzCH:SOH2CH20N 0001-:012 1,4-bis-(B-Oyanoethylmercapto)butane NC- -CHzOHzCH2- H2CH2 H2-s- H2*OH2-ON 0012-. 012 B-Propylmercaptopropionitlile CHaOH2CH2-SCH2-CH2CN- I 0005-. 006 fl-Allylmercaptopropionitrile CH2=OH GH2 SUH2CH2ON 0005. 006 B-Pr0pargylmercaptopriopionitrile OHEC-CHPS-OHPGHPCN 0005-. 006 3-(fi-Diethylaminoethylmercapto)-propionitrile (C2H5)2NC2H4-S-C2H4CN 002,-. 015 Bls-[2-(fl-Oyanoethoxy)'ethyl] sulfide NG-(CH:)2O(OHz):S-(CHz)2-0(CHa)2CN 002-. 015 2-(fl-Oyanoethoxy)ethyl-2-cyanoethyl sulfide N O-(OHa)20-( 2)tS-(- z)z 0021015 H2N\ I I V I S-BCyanoethylthioureta 0 VS-'C2H4CN- 002-. 015

p I C m-N. t N,N-I5ipheny1-S-fl cyanoethylthiourea H I C-S-C:H4CN .002-.015

I C Htr-N k CH; a 8 Bis-(Z-Oyanopropyl) sulfide N OCiH-OHa S--CHzOHCN and unsaturated aliphatic sulfonates, sulfoamides, and sulfimides. Within the scope of the expression aromatic and unsaturated aliphatic sulfonates, sulfoamides and sulfimides are included the acids and their salts such as the sodium, potassium, nickel, cobalt, and iron salts thereof. Specifically, the class includes aryl and unsaturated alkyl sulfonates, sulfimides and sulfonamides, and the foregoing salts thereof wherein the number of carbon atoms in any aryl nucleus is from 6 to 10 and in any unsaturated alkyl group is from 1 to 10, and substitution products of the foregoing wherein the substituents are chosen from the class of alkyl groups having 1 to 4 carbon atoms, chlorine, CH and phenyl. fonarnides, sulfimides, and sulfonates are frequently referred to as carriers or regulators in the art of nickel plating, and accordingly, are sometimes so-called herein. These carriers produce a degree of brightness without a cooperating brightener. duce sufficient brightness when utilized as the sole brightening additive in acid nickel plating solutions to be considered as producing a full, bright plate. The carriers or regulators constituting this second class of addition agents are soluble in the plating solution (for example, in a solution consisting of 240 grams of NiSO .6H O, 37.5 grams of NiCl .6H O, 37.5 grams of H BO and water to make a liter) to the extent of at least 0.05 gram per liter.

Typical compounds illustrating the aryl and unsaturated alkyl sulfonamides, sulfimides and sulfonates are set forth in Table II. With respect to the aromatic sulfonic acids and sulfonamides and sulfimides various substituents in the ring structure are evident in the formulas indicated.

The brightening addition agent should be dissolved in the aqueous plating bath in an amount ranging from .0001 to'.015 gram per liter. Optimum results are usually secured if the concentration of the brighteners dissolved in the aqueous plating bath ranges from about .001 to about .005 gram of brightener per liter of solution. The amount of carrier dissolved in the acid nickel plating solution ranges from .05 gram per liter to 20 grams per liter, best results being obtained when the carrier is dissolved in the plating solution in amounts from about 2 to about grams per liter.

TABLE H Aromatic sulfonamides Benzene monosulfonamide o sSOaN saccharine, sodium salt CaHlSOaCONNSL p-Toluenesulfonamide CHaCoHsSOaNHa Trichlorodibenzenesulfonamide CIBCGHSSOSiNHSOZCBHAC]. Di-fl-naphthalenesulfonamide CH7S02NHs02C10H7 4-carboxydibenzenesulfonamide eHnS02NHS02CeH4COOH N,N'-bis (phenylsulfouyl) -4,i=-diphenyldisulfonamlde CcHaSOaNHSOzCsHaCeHaSOaNHSOaCaHs p,p-Oxy-bis(dibenzenesulfonamide) CUHESOQNHSO2CGH4OCBH4SO2NHSOZCGH5 p,p'-Methylene-bis-(dibenzenesulfonamide) CaHsSOaNHSOeCeHaCHaCoHaSOaNHSoecoHs Aromatic sulfonates Benzene monosulfonic acid 'CoHE Os Benzene disulfonic acid CoHl $0311) a Nickel naphthalene disulfonate C1oHa( SO20) 2N1 Cobalt naphthalene disulfouate (CoHeSOs)2C0 Nickel benzene monosulfonate CoH5SOs)2N1 Dichlorobenzene disulfonic acid CleCoHz SOaH) 2 Toluene sulfonic acid CHSCBHQSO2H Diphenyl sulfonic acid CBHSCBHASOSH Thiophene sulfonic acid C4HsS.SOaH Diphenyl sulfone CoHsSOaCaHs Naphthalene trlsulfonic acid CmHs(SOaOH)s Nevertheless, they do not pro The organic sul- Unsaturated aliphatic sulfonamides and sulfonic acids Sodium vinyl sulfonate H2C:CHSOsNtL Sodium allyl sulfonate H20: CHCHeSOaNB. Vinyl sulfonamide H2C:CHSO2NH2 Allyl sulfonamide H20: CHCHaSOaNHz The constituents of the plating bath, according to the preferred practice of the invention, are (1) water, (2) nickel sulfate, nickel chloride, or a mixture of nickel sulfate and nickel chloride, (3) the brightener, (4) a sulfonate, a sulfonamide, a sulfimide, or one or more sulfonates, sulfonamides, sulfimides or mixtures thereof of the type previously indicated, (5) and a wetting agent (optional). An additional ingredient of the solution which is desirable is a buffering agent such as boric acid, formic acid, or the like.

It will be noted that in reference to the major constituent of the nickel plating solution, the solutions are similar to the well known all chloride, all sulfate," and sulfate-chloride or Watts" type acid nickel plating solutions. The essential novel feature of the invention is the use of an acid nickel plating solution having one or more nickel electrolytes selected from nickel sulfate and nickel chloride and additionally containing cooperating brightening agents, one of which is at least one carrier selected from the group consisting of unsaturated aliphatic sulfonamides, unsaturated aliphatic sulfimides, unsaturated aliphatic sulfontes, aromatic sulfonamides, aromatic sulfimides nd aromatic sulfonates, and the other of which is a small amount of a brightener of the type heretofore indicated. I

The basic solutions in connection with which the bright ductile nickel deposits are realized when containing the! cooperating addition agents dissolved therein are as follows:

All sulfate N1SO4.7H2O to 400 grams, preferably 200 to 300 grams. Boric acid 0 to 60 grams, preferably 10 to 40 grams. Wetting agent (e.g. sodium lauryl sulfate) 0 to 0.5 gram, preferably 0.05 to 0.2 gram.

H2O to make 1,000 cc.

All ChlOl'ldE NiCl- .6H20 50 to 250 grams, preferably 100 to 200 grams.

Boric acid 0 to 60 grams, preferably 10 to 40 grams.

Wetting agent (e.g.

lauryl sulfate 0 to 0.5 gram, preferably 0.05 to .2 gram. H2O to make 1,000 cc.

Sulfate-chloride Watts type NlSO4-7H2O 100 to 400 grams, preferably 200 to 300 grams. NlCl2.6H2O 10 to 60 grams, preferably 25 to 40 grams.

to 50 grams, preferably 15 to 40 grams.

to 0.5 ram, preferably 0.025 to .2 gram.

Boric acid 0 All All Watts Sulfate Chloride an 34. 5 2. 4-4. a 3-4. 5 Temperature, F 120-160 100-150 -455 Cathode Current Density (amp/iii).-- 20 40 60-200 30- 70 Nickel Chloride, g./l

by-electrolyzing the electroplating :solution between an pending application, Serial Number 701,713, filed-Des; anode and a buffed brass cathode. Similar results may 75 c'ernber l0, l95 7,now ab andoned.

In the preparation of the plating solution according be securedon other types of cathodes conventionallyemto the invention, I add to each of the foregoing basic soluployed in acid nickel plating processes utilizing solutions tions a suitable quantity of the brightener and also one of the type indicated herein.

TABLE III Nickel Sulfate 300 300 300 300 300 3 Nickel Fluobdr t e g./1 9 .599. 99. ni l l .Q Nickel Chloride, g./l 3s 3s 38 as as as 3s 38 as 300 Borlc Acid, g./1 3s 3s 38 3s 3s 3s 38 3s 38 10 3s Allyl Sulfonic Acid, g./1 Dibenzene Sulfonamide (Nickel salt), g./l 3 Naphthalene Disulfate, g./L Allyl Sulfouamide Bi-dibenzenesulionamide, g. /1 Dibenzenesulfonamide ether, g./1 Saccharin (sodium salt), g./l Toluene sulfonamide, g./l fi-Propylmercaptopropionitrlle. fl-Allylmercaptopropionitrile ,B-Propargylmercaptopropiouitrile. B,B-Thiodipropionitrile a,m-Thiodiethanenitrile 1,2 bis (fi Cyanoethylmercapto) ethane 1,4 bis (fl Oyanoethylmercapto) butane 005 3(8-Diethylaminoethylmercapto)- propionitrile Bis? (fi Cyanoe fi e 2-(fi-Cyanoethoxy)ethyl-2-cyanoethyl sulfidea S-B-Cyanoethylthiourea- N,N Diphenyl- S -B- Cyanoethyl thiourea Bis-(2-Oyanopropyl)sulfide Goumarin, g. Ctf1tth)ode Current Density, (amp./

. 5O Temperature, F- 140 140 160 I 140 140 150 140 140 140 140 140 Agitation (1R. C-R. Ail (LR. (LR. Air C.R. C.R. O.R. C.R. C.R.

Nickel Sulfate, g./1 10 300 300 300 300 300 300 300 300 300 Nickel Fluoborate, g

Boric Acid, g./l Allyl Sulfonic Acid, g ./l Dibeuzene Sulfonemnle (Nickel salt), g./1 Naphthalene Disulfonate, g./1 Allyl Sulfonamide Bi-dibenzenesulfonamide, g./l Dibenzenesulfonamide ether, g./1 Saocharin (sodium salt), g./l Toluene sulfonarnide, g./l B-Propylmercaptopropionltrlle fi-Allylruercaptopropionitrile fl-Propargylmercaptopropiomtrile fl,fl-Thiodipropionitrile a,a-Thiodiethanenitrile 1,2-bis-(B-Oyanoethylmercapto)ethane. 1,4-bis- (fl-Oyan0ethylmercapto)butane 8(5-5iethylamiuoethylmercapto)-propion ifi e S-fi-Oyanoethylthiourea N,N-Diphenyl-S-fl-Cyanoethyl thi0urea Bis-(2-OyanopropyDsulfide Ooumarin, g./l Cathode Current Density, (amp/ft. Temperature, F i Agitation 1 C.R.=Cathoderod. V I a or more of the unsaturated aliphatic, or aromatic. sul- According to one form of the invention, theaddition fonamides, sulfimides, and sulf onates. The plating solu 0t coumarin, or certain of its derivatives to the plating' tion, for the best results, contains an antipitting agent al- "solution in amounts from .03 to .25 gram-per liter and though the deposits may be suitable for some purposes preferably about .1 gram per liter, .rnaterially aids in without elimintaing pitting. 'Sodium lauryl sulfate or securing "a smooth nickel deposit. The'substituted couother wetting agents such as the sodium sulfate derivative marin derivatives Where the substituents are. alkyl oracyl of 7-ethyl-2-methyl-undecanol-4 and the dihexyl ester of groups not exceeding 4 carbon atoms,-halogen, hydroxy' sodium sulfosuccinic acid may be used as an antipitting or carboxy group's maybe employed. Typical examples agent, although its use is not essential and other wetting of substitutedcoumarins are t-methyl coumarin, ,6-chloro agents or mixtures of Wetting agents may be used to coumarin, 3-acetyl coumarin,'coumaIin-3-oarboxylic acid,

control the pitting. For some purposes pitting may be 4,8-dimethy-l cournarin, '7-hydroxy coumarin,=6-carb,ociy

tolerated and sometimes very little pitting occurs. 7 -coumarin, 3-chloro bouniarimqand 3-methyl eoumarin. Specific examples of electroplating solutions containing Thus, cournarin' or its said derivatives'n'ray beldiss'olved different cooperating brighteners and carriers are illusin the nickel plating solutionsrcontaining the cooperating trated, in :Table'III. The operating ccnditiojns forobbrightening agent.s. and found to exe t al'eve'ling taining bright ductile nickel deposits are also set forth smoothing action such that bright, ductile,2nickel depos1ts in the table. In each case a brightnickel deposit of of excellent smoothnessiare obtained;

fiom .05 to about 1 mil thick or thicker; may be secured a This. application is a. continuation-in-part oflmyeco- Having thus described the invention, what I claim is:

1. A nickel electroplating bath comprising an aqueous solution of a nickel electrolyte selected from the group consisting of nickel sulfate, nickel chloride, and mixtures thereof, said solution also containing cooperating brightening addition agents, one of said brightening addition agents being at least one organic compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addition agents being a compound of the formula A-fiS(CH C'N, wherein n is an integer from 1 to 4 and A is selected from radicals of the class consisting of:

m being an integer from 1 to 4; alkyl, 1 to 4 carbon atoms; alkenyl, l to 4 carbon atoms; alkynyl, l to 4 carbon atoms; R NC H where R is chosen from alkyl, alkenyl and alkynyl radicals of from 1 to 4 carbon atoms;

RzN-=N-R where R is independently chosen from alkyl, alkenyl, and alkynyl radicals of from 1 to 4 carbon atoms; and compounds corresponding to the foregoing compounds wherein OCH CH has been substituted for (CH the first said brightening addition agent being present in said solution to the extent of from 0.05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from 0.0001 to 0.015 gram per liter.

2. A nickelelectroplating bath comprising an aqueous solution of a nickel electrolyte selected from the group consisting of nickel sulfate, nickel chloride, and mixtures thereof, said solution also containing cooperating brightening addition agents, one of said brightening addition agents being at least one organic compound se lected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonarnides and sulfimides and the second of said agents being a thioalkylene nitrile having from 1 to 4 carbon atoms in the alkylene group, the first said brightening addition agent being present in said solution to the extent of from .05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from .0001 to .015 gram per liter.

3. A nickel electroplating bath comprising an aqueous solution of a nickel electrolyte selected from the group consisting of nickel sulfate, nickel chloride, and mixtures thereof, said solution also containing cooperating brightening addition agents, one of said brightening addition agents being at least one organic compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addition agents being a thiodialkylene nitrile having from 1 to 4 carbon atoms in the alkylene group, the first said brightening addition agent being present in said solution to the extent of from .05 to 20 grams per liter and the second said brightening agent being present in said solution to the extent of from .0001 to .015 gram per liter.

4. A nickel electroplating bath comprising an aqueous solution of a nickel electrolyte selected from the group consisting of nickel sulfate, nickel chloride, and mixtures thereof, said solution also containing cooperating brightening addition agents, one of said brightening addition agents being at least one organic compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addition agents being a thioalkoxy nitrile having from 1 to 4 carbon atoms in the alkoxy group, the first said brightening addition agent 8 being present in said solution to the extent of from .05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from .0001 to .015 gram per liter.

5. A nickel electroplating bath comprising an aqueous solution of nickel electrolyte selected from the group consisting of nickel sulfate, nickel chloride, and mixtures thereof, said solution also containing cooperating brightening addition agents, one of said brightening addition agents being at least one organic compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addition agents being a thiodialkoxy nitrile having from 1 to 4 carbon atoms in the alkoxy group, the first said brightening addition agent being present in said solution to the extent of from .05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from .0001 to .015 gram per liter.

6. An acid nickel electroplating solution comprising in addition to Water, nickel sulfate equivalent to from to 400 grams per liter of NiSO .7H O, nickel chloride equivalent to from 10 to 60 grams per liter of NiCl .6H O, a buffering agent and cooperating, brightening addition agents, one of said brightening addition agents being a compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addition agents being a B,fi'-thiodipr0pionitrile, the first said brightening addition agent being present in said solution to the extent of from 0.05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from 0.0005 to 0.006 gram per liter.

addition to water, nickel sulfate equivalent to from 100 to 400 grams per liter of NiSO .7H O, nickel chloride equivalent to from 10 to 60 grams per liter of NiCl .6H O, a bulfering agent and cooperating, brightening addition agents, one of said brightening addition agents being a compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addi tion agents being a,a'-thiodiethanenitrile, the first said brightening addition agent being present in said solution to the extent of from 0.05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from 0.0005 to 0.006 gram per liter.

8. An acid nickel electroplating solution comprising in addition to water, nickel sulfate equivalent to from 100 to 400 grams per liter of NiSO .7H O, nickel chloride equivalent to from 10 to 60 grams per liter of NiCl .6H O, a bufi'ering agent and cooperating, brightening addition agents, one of said brightening addition agents being a compound selected from the group consisting of aromatic and unsaturated aliphatic sulfonates, sulfonamides and sulfimides and the second of said brightening addi tion agents being 1,2-bis-(fl-cyanoethylmercapto) ethane, the first said brightening addition agent being present in said solution to the extent of from 0.05 to 20 grams per liter and the second said brightening addition agent being present in said solution to the extent of from 0.0001 to 0.012 gram per liter.

References Cited in the file of this patent UNITED STATES PATENTS UNIT'E STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,978,391 April 4, 1961 Arthur H. Du Rose It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 28, for "alkyny'" read alkynyl lines 71 and 72, for "sulfoamides" read sulfonamides column 3, lines 1 and 3, for "sulfoamides", each occurrence,

read sulfonamides 3"; column 4, line 29, for "sulfontes" read sulfonates 1.3 columns 5 and 6, Table III, first column thereof, seventh item, for "Naphthalene Disulfate" read Naphthalene Disulfonate column 5, line 60', for "elimintaing" read eliminating column 6, line 60, for "The substituted" read Substituted 5, column 8, line 37, for "NiSO JH O" read N'iSO Q'II-I O Signed and sealed this 22nd day of August 1961.

(SEAL) Attest ERNEST W, SWIDER DAVID L, A

Attesting Officer Commissioner of Patents 

1. A NICKEL ELECTROPLATING BATH COMPRISING AN AQUEOUS SOLUTION OF A NICKEL ELECTROLYTE SELECTED FROM THE GROUP CONSISTING OF NICKEL SULFATE, NICKEL CHLORIDE, AND MIXTURES THEREOF, SAID SOLUTION ALSO CONTAINING COOPERATING BRIGHTENING ADDITION AGENTS, ONE OF SAID BRIGHTENING ADDITION AGENTS BEING AT LEAST ONE ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF AROMATIC AND UNSATURATED ALIPHATIC SULFONATES, SULFONAMIDES AND SULFIMIDES AND THE SECOND OF SAID BRIGHTENING ADDITION AGENTS BEING A COMPOUND OF THE FORMULA A-S-(CH2)NCN, WHEREIN N IS AN INTEGER FROM 1 TO 4 AND A IS SELECTED FROM RADICALS OF THE CLASS CONSISTING OF: 